Reversible resistivity-switching (RRS) materials may be used as storage elements in memory arrays. For example, U.S. Pat. No. 7,812,404, filed May 9, 2005 and titled “NON-VOLATILE MEMORY CELL COMPRISING A DIODE AND A RESISTANCE-SWITCHING MATERIAL”, which is hereby incorporated by reference herein in its entirety, describes a rewriteable non-volatile memory cell that includes a diode coupled in series with an RRS material such as a metal oxide or metal nitride.
Modulation of the resistivity of metal oxide and other RRS materials requires use of voltages and/or currents that may be difficult to achieve efficiently with conventional diodes, particularly when large arrays of RRS material storage elements are employed (e.g., such as when a low leakage current is desired for “unselected” storage elements in the array). Accordingly, a need exists for diodes with I-V characteristics that are compatible with metal oxide or other RRS material storage elements and/or arrays, and for methods of forming such diodes.